Implement structured genotype-to-phenotype expression

[Spbd1]

Motivation

• Provide a deterministic mapping from the compact 128-bit computational genotype into a structured, typed phenotype object covering coat, pattern, morphology, mobility, cognition, thermal/camouflage traits and circadian tendency.
• Ensure numeric phenotype values are normalized to the inclusive 0–1 range and remain compatible with the older abstract gene Genome representation.

Description

• Added pishiegen/phenotype/traits.py which defines a Phenotype dataclass, PHENOTYPE_FIELDS, a clamp helper, traits serialization and a numeric value() accessor that returns continuous trait values for fitness scoring.
• Added pishiegen/phenotype/dominance.py implementing coat-allele decoding, a simple dominance ranking and dilution-as-modifier behavior.
• Reworked pishiegen/phenotype/expression.py to accept pishiegen.genome.encoding.Genome or a raw 128-bit integer, decode schema fields, and compute coat, hidden coat, pattern/agouti, pattern intensity, fur length/type, ear type/size, tail type, polydactyly, colorpoint/albino status, health risk, cold/heat tolerance (modified by fur and ear size), biome-relevant camouflage/wetland mobility, agility (tail and polydactyly modifiers), sensory acuity (ear modifiers), intelligence, and circadian type, while preserving extra_traits when expressing the older abstract gene Genome.
• Exported the phenotype API from pishiegen/phenotype/__init__.py and added tests/test_phenotype_expression.py which checks a known compact genome, agouti suppression, polydactyly behavior, required output fields, and 0–1 clamping for normalized scores.

Testing

• Ran the full test suite with python -m pytest -q, which executed the new tests/test_phenotype_expression.py along with existing tests and completed successfully.
• Ran python -m compileall pishiegen tests to ensure modules compile without errors and it succeeded.

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Codex Task